hanker excavation The radio doorbell support 900feet -LRB- 274m -RRB- operation range in afford space. IP44 seal Transmitter The transmitter is, so you can install it on the outdoors for your convenience. Easy to Leave Message There a compartment at the collide with of the transmitter that you can delivery some news to your visitors or they can leave some message to you. Easy Installation Just receiver into an electric outlet -LRB- no batteries required for pipage receiver -RRB- and install the transmitter. Four levels for your choice : 4 levels of changeable fathom volume give you play assure over the fathom of your door chime. morality for nap time without worrying your infant or youth child when they are asleep. : Receiver excavation Voltage : AC110V -LRB- US -RRB- / AC220V -LRB- EU UK AU -RRB- Battery in Transmitter : 12V 23A alkaline battery Operation Range : over 900 feet -LRB- Open Space -RRB- Selectable Ring tone : 52pcs Volume Range : 30-110db ; 4 levels NOTE : What You Should Know Before Installation Doorbell 's signal can be effected by metal, walls, concretes and interference signal from strange electronics. Doorbells can within 900 feet in afford and non-interference environment. Generally, it can within 200 ~ 700 feet through the metal security doors and walls depending on the medicament using environment. Please do them within environment with less obstacles. Package : As the picture shown.